The present disclosure relates generally to semiconductor techniques. More specifically, embodiments of the present disclosure provide methods and systems for efficiently dicing substrates containing gallium and nitrogen material. Gallium and nitrogen containing substrates are often used in manufacturing light emitting diodes (LEDs), lasers, and other devices, are typically formed by crystal growth methods, and contain high-dislocation areas that are usable in manufacturing devices. In various embodiments, this disclosure provides techniques for dicing substrates based on patterns of the high-dislocation areas.
In the late 1800's, Thomas Edison invented the light bulb. The conventional light bulb, commonly called the “Edison bulb,” has been used for over one hundred years. The conventional light bulb uses a tungsten filament enclosed in a glass bulb sealed in a base, which is screwed into a socket. The socket is coupled to an AC power or DC power source. The conventional light bulb can be found commonly in houses, buildings, outdoor lightings, and other areas requiring light. Unfortunately, drawbacks exist with the conventional Edison light bulb. That is, the conventional light bulb dissipates much thermal energy. More than 90% of the energy used for the conventional light bulb dissipates as thermal energy. Additionally, the conventional light bulb eventually fails due to evaporation of the tungsten filament.
To overcome some of the drawbacks of the conventional light bulb, fluorescent lighting has been developed. Fluorescent lighting uses an optically clear tube structure filled with a noble gas and typically also contains mercury. A pair of electrodes is coupled between the gas and to an alternating power source through a ballast device. Once the mercury has been excited, it discharges to emit UV light. Typically, the optically clear tube is coated with phosphors, which are excited by the UV light to provide white light. Many building structures use fluorescent lighting and, more recently, fluorescent lighting has been fitted onto a base structure, which couples into a standard socket.
Solid state lighting techniques have also been used. Solid state lighting relies upon semiconductor materials to produce light emitting diodes, commonly called LEDs. At first, red LEDs were demonstrated and introduced into commerce. Modern red LEDs use Aluminum Indium Gallium Phosphide or AlInGaP semiconductor materials. Most recently, Shuji Nakamura pioneered the use of InGaN materials to produce LEDs emitting light in the blue color range for blue LEDs. The blue colored LEDs led to innovations such as solid-state white lighting, the blue laser diode, which in turn enabled the Blu-Ray™ DVD player (trademark of the Blu-Ray Disc Association), and other developments. Blue, violet, or ultraviolet-emitting devices based on InGaN are used in conjunction with phosphors to provide white LEDs. Other colored LEDs have also been proposed.
InGaN and GaN based devices, such as LED and laser devices, are often manufactured from substrates that are formed by crystal growth processes. Various conventional techniques have been used in the past to use this type of substrate. Unfortunately, the conventional techniques are often inadequate, either providing an average dislocation density that is too high for device reliability, or in the case of very low-dislocation-density substrates, the presence of localized high-dislocation density regions (e.g., dislocation bundle centers) which are deleterious to device performance.
The organization of the dislocation bundle centers suggests that the disclosed dicing techniques can optimize utilization of the substrate (e.g., dicing in a manner so as to produce the desired devices, while eliminating or reducing waste).
Therefore, it is desirable to have improved techniques for processing devices gallium and nitrogen containing substrates.